JP6874308B2 - Mirror surface decorative sheet and decorative board using it - Google Patents

Description

The present invention relates to a decorative sheet to which a printing technique is applied, and particularly to a mirror surface decorative sheet having high gloss, excellent vividness, weather resistance and surface physical properties, and a decorative board using the same. ..

Conventionally, decorative sheets have been widely used as surface materials for furniture and housing members. This has the advantage that, in addition to being inexpensive and stable in terms of price as compared with the case of using a natural material, the variation can be reduced as compared with the case of using a natural material in terms of performance.

In addition, the range of applications of decorative sheets has been expanded by developing those with excellent weather resistance and surface physical characteristics. In addition, the development of printing technology has made it possible to express high-quality wood grain and highly-designed patterns, and the development of products with richer design is also a major factor in the spread of decorative sheets.

Conventionally, a polyvinyl chloride resin film printed with a desired pattern has been the mainstream. In recent years, in addition to that, in consideration of environmental issues, a decorative sheet using a non-chlorine resin film such as a polyolefin resin, which does not generate harmful substances such as hydrogen chloride or dioxin during combustion. Has also been developed and is becoming widely used.

In the process of pursuing design, there are many applications that require a highly glossy surface. For example, in applications such as kitchen doors and bathroom interiors, in addition to high surface gloss, extremely high freshness is required compared to other ordinary applications, and polyvinyl chloride resin films and polyolefins are required. It cannot be handled with a based resin film.

This is because the polyvinyl chloride resin film is soft and lacks thickness accuracy and surface smoothness, and the polyolefin resin has high surface haze due to its high crystallinity, and both have weak scratch resistance. ..

Therefore, as a decorative sheet for applications that require high gloss and high freshness, a mirror surface makeup having a structure in which a polyethylene terephthalate film having excellent transparency, surface smoothness, scratch resistance, etc. is arranged on the surface has been conventionally used. Sheets are mainly used.

For example, a transparent polyethylene terephthalate film in which a desired pattern is pre-printed on the back surface of a concealing base film made of a colored polyvinyl chloride resin film or a colored polyolefin resin film via an adhesive layer. The ones made by pasting together are also commercialized.

In fact, in Patent Document 1, in a decorative sheet in which a printing ink layer is provided between thermoplastic resin films, a vinyl chloride film is used as the base thermoplastic resin, and a polyethylene terephthalate film is used as the surface thermoplastic resin. It is proposed to place.

Further, Patent Document 2 proposes a high-quality decorative sheet in which a colored polyolefin film is printed and a transparent polyethylene terephthalate film is laminated on the surface thereof.

However, in each case, the outermost layer is composed of a polyethylene terephthalate film, which is insufficient in weather resistance and surface scratch resistance. When the surface gloss is high, changes in surface gloss, whitening, scratches, etc. are more noticeable, and the physical characteristics of the surface are also required to be more advanced.

Further, in an attempt to overcome this point, an attempt has been made to provide a hard coat layer on the outer layer of the polyethylene terephthalate film, but problems in appearance such as interference fringes due to the thin film have been pointed out.

Japanese Unexamined Patent Publication No. 4-238026 Japanese Unexamined Patent Publication No. 10-258488

The present invention has been made in view of such a situation, and it is an object of the present invention to provide a mirror surface decorative sheet having excellent mirror surface properties, excellent weather resistance, and excellent design properties, and a decorative board using the same. ..

As a means for solving the above problems, the invention according to claim 1 is a decorative sheet composed of a thermoplastic base material plastic film layer, a pattern layer, and a biaxially stretched polyethylene terephthalate film layer.
A hard coat layer is provided on the outside of the biaxially stretched polyethylene terephthalate film layer by adding 0.2 to 0.6 parts by weight of a benzotriazole-based ultraviolet absorber to urethane acrylate to which a photoinitiator has been added. It is a mirror surface decorative sheet.

The invention according to claim 2 is the mirror decorative sheet according to claim 1, wherein the thickness of the hard coat layer is 4 to 8 μm.

The invention according to claim 3 is a decorative board using the mirror-finished decorative sheet according to claim 1 or 2.

According to the present invention, it is possible to provide a mirror surface decorative sheet having excellent mirror surface properties, excellent weather resistance, and excellent design properties, and a decorative board using the same.

That is, the mirror surface property and the design property can be realized by arranging the polyethylene terephthalate film on the pattern layer by printing, and the weather resistance can be realized by adding the ultraviolet absorber to the hard coat layer. Further, it is possible to improve the scratch resistance by the hard coat layer.

In particular, according to the second aspect of the present invention, it is possible to provide a mirror-finished decorative sheet having excellent mirror surface properties, excellent weather resistance, suppressing interference fringes of the hard coat layer, and excellent design properties.

That is, by setting the thickness of the hard coat layer to 4 to 8 μm, the occurrence of interference fringes can be suppressed, and a mirror-finished decorative sheet having excellent scratch resistance can be realized.

In particular, according to the invention of claim 3, by laminating the mirror surface decorative sheet to, for example, a wooden plate or a metal plate, a decorative plate having excellent mirror surface property, excellent weather resistance, and excellent design property is provided. It is possible to do.

FIG. 1 is a schematic partial cross-sectional view for explaining one embodiment of a mirror-finished decorative sheet and one embodiment of a decorative board using the mirror-surface decorative sheet according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to FIG. However, the present invention is not limited to the examples shown here. The present invention is limited by the claims.

FIG. 1 is a schematic partial cross-sectional view for explaining one embodiment of a mirror-finished decorative sheet and one embodiment of a decorative board using the mirror-finished decorative sheet according to the present invention.

The mirror surface decorative sheet according to the present invention is a decorative sheet formed by laminating a thermoplastic base material plastic film layer (1), a pattern layer (2), and a biaxially stretched polyethylene terephthalate film layer (4).

As the pattern layer, the pattern layer (2) is formed on the thermoplastic base material plastic film layer (1) by using a printing method. Further, the biaxially stretched polyethylene terephthalate film layer (4) is laminated with the dry laminate layer (3) as an adhesive layer.

On the outer surface of the biaxially stretched polyethylene terephthalate film layer (4), 0.2 to 0.6 parts by weight of a benzotriazole-based ultraviolet absorber was further added to a urethane acrylate resin to which a photoinitiator had been added. It has a coat layer (6).

When the pattern layer (2) is provided by the printing method, the thermoplastic base material plastic film layer (1) is a film to be printed, and a generally colored plastic film is used for the purpose of designability and concealment. It is also possible to use a transparent film to form a colored concealing layer on the entire surface by printing or coating.

The plastic material used for the thermoplastic base material plastic film layer (1) is not limited as long as the film can be formed, and for example, a polyvinyl chloride resin can be used. In this case, there is a problem of generation of hydrogen chloride and dioxin in incineration such as when discarded. Therefore, when considering this point, for example, a polyolefin-based resin can be used and is preferable.

The printing ink used for the pattern layer (2) can be appropriately selected from those having adhesion to the thermoplastic base material plastic film layer (1), printability, and satisfying the required light resistance performance. it can.

The printing method is not limited, and can be appropriately selected from known printing methods such as a gravure printing method, an offset printing method, a silk screen printing method, and an inkjet printing method.

By laminating the biaxially stretched polyethylene terephthalate film layer (4) on the thermoplastic base material plastic film layer (1) via the pattern layer (2), it is effective in increasing the mirror surface property of the surface. The smoothness of the biaxially stretched polyethylene terephthalate film layer (4) is one of the main factors. This lamination can be performed by providing, for example, a dry laminate layer (3).

Further, in order to further strengthen the adhesion of the laminate, it is preferable to perform, for example, a corona discharge treatment on the dry laminate layer (3) side of the biaxially stretched polyethylene terephthalate film layer (4).

As a result of diligent studies, we have found that it is practically preferable to use a biaxially stretched polyethylene terephthalate film layer (4) having a haze value of 4 to 6%.

This is because, when the haze value is in this range, the mirror surface decorative sheet (10) does not hinder the mirror surface property, and the surface has a certain slipperiness, so that it is suitable for winding in a roll shape in production. Due to the excellent effect.

The mirror-finished decorative sheet according to the present invention has a hard coat layer (6) on the surface of the biaxially stretched polyethylene terephthalate film layer (4) opposite to the surface facing the thermoplastic plastic film layer (1). .. The hard coat layer (6) is a hard coat layer in which 0.2 to 0.6 parts by weight of a benzotriazole-based ultraviolet absorber is added to a urethane acrylate resin to which a photoinitiator has been added.

The hard coat has the effect of improving the scratch resistance on the surface of the mirror surface decorative sheet (10), but the weather resistance is improved by adding a benzotriazole-based ultraviolet absorber to the urethane acrylate resin to which the photoinitiator has been added. Can be planned. As a result of repeated studies, it was found that it is optimal to add 0.2 to 0.6 parts by weight.

The evaluation method for weather resistance is as follows.
The device used is Metal Weather (manufactured by Daipla Wintes Co., Ltd.).
Light energy: 65mW / m ²
Cycle: L (irradiation) + D (condensation) + R (darkness) = 20h + 4h + 0.01h
As a determination method, after the test for 192 hours, the hard coat layer is visually observed to determine whether the hard coat layer has a coating film abnormality such as color change or whitening, and whether or not the hard coat layer is peeled off.

By providing the hard coat layer (6) on the biaxially stretched polyethylene terephthalate film layer (4), a striped pattern is observed when the mirror surface decorative sheet (10) is viewed from the hard coat layer (6) side. Sometimes. This is a phenomenon in which interference fringes are generated due to the difference in refractive index between the hard coat layer (6) and the biaxially stretched polyethylene terephthalate film layer (4), which hinders the design.

In the present invention, we have found that the occurrence of interference fringes can be reduced by setting the thickness of the hard coat layer (6) in the range of 4 to 8 μm. That is, it is possible to avoid deterioration of design due to interference fringes. Further, if the hard coat layer (6) has a thickness in this range, it is suitable without impairing the performance as a hard coat.

The material of the hard coat layer (6) is not limited, but generally, a resin of a type that is crosslinked by irradiation with ionizing radiation or non-ionizing radiation is preferably used. For example, in the case of ionizing radiation, an electron beam can be used, and in the case of non-ionizing radiation, ultraviolet rays can be used. Further, as the resin type, for example, acrylic type or urethane type resin can be used alone or in combination.

A known coating device can be used for forming the hard coat layer (6), and for example, a method such as direct gravure coating, direct reverse gravure coating, micro gravure coating, die coating, etc. can be used, and a method is appropriately selected. be able to.

Further, in order to further strengthen the adhesion between the hard coat layer (6) and the biaxially stretched polyethylene terephthalate film layer (4), for example, a corona discharge treatment is performed on the surface of the biaxially stretched polyethylene terephthalate film layer (4). Can be applied. Alternatively, an anchor layer (5) may be provided by coating or the like.

The mirror-finished decorative sheet (10) thus constructed can be made into a decorative plate (20) by laminating it with a base material layer (9) such as a wooden plate or a metal plate. In this lamination, the primer layer (7) provided on the surface of the mirror surface decorative sheet (10) opposite to the hard coat layer (6) and the base material layer (9) are combined with the adhesive layer (8). By laminating through the above, a decorative plate (20) having a mirror surface can be realized.

As described above, according to the present invention, it is possible to provide a mirror surface decorative sheet having excellent mirror surface properties, excellent weather resistance, and excellent design properties, and a decorative board using the same.

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples shown here. The present invention is limited by the claims.

<Example 1>
(Creation of mirror decorative sheet)
A two-component urethane primer resin layer (thickness 1 μm) is placed on the back surface of a polyolefin-based resin sheet (“Rivester TPO 70 μm thick” manufactured by Riken Technos Co., Ltd.) that has been subjected to abstract pattern printing with two-component urethane resin ink. Provided.

Next, as a hard coat layer on a biaxially stretched polyethylene terephthalate film layer having a thickness of 100 μm which has been subjected to corona treatment in advance, 0.4 parts by weight of a benzotriazole ultraviolet absorber is added to a urethane acrylate resin to which a photoinitiator has been added. Is diluted to an appropriate viscosity with a diluting solvent, and then coated by a direct reverse gravure method (peripheral speed ratio 100%) so that the coating thickness after drying is 6 μm, and then a high-intensity high-pressure mercury lamp. Was irradiated and cured.

Next, the opposite surface of the hard coat layer of the biaxially stretched polyethylene terephthalate film was subjected to corona treatment, and 10 parts by weight of hexamitylene diisocyanate isocyanate was added to 100 parts by weight of a mixed resin of an acrylic resin and a polyurethane polyol resin. Was mixed and diluted to an appropriate viscosity, and the coating liquid ^{was applied to a coating amount of 6 g / m 2} after drying by a direct gravure coating method, and dry-laminated to complete a mirror-finished decorative sheet according to the present invention.

(Creation of veneer)
Next, a two-component vinyl acetate resin aqueous emulsion adhesive (coating amount 60 g / m ²⁾ is applied to a medium density fiberboard (MDF) having a thickness of 5 mm, and the mirror surface decorative sheet is attached to prepare a decorative board. did.

<Comparative example 1>
(Creation of decorative sheet)
In Example 1, a mirror-finished decorative sheet according to the present invention was produced in the same manner as in Example 1 except that an ultraviolet absorber was not added to the hard coat layer.

(Creation of veneer)
Next, a two-component vinyl acetate resin aqueous emulsion adhesive (coating amount 60 g / m ²⁾ is applied to a medium density fiberboard (MDF) having a thickness of 5 mm, and the mirror surface decorative sheet is attached to prepare a decorative board. did.

<Evaluation items and evaluation methods>
The evaluation items and evaluation methods are as follows.
Tests and evaluations were carried out by each evaluation method using the mirror surface decorative sheet prepared in Example 1 and Comparative Example 1 or the decorative board using the mirror surface decorative sheet as a sample.

(Interference fringes)
The appearance of the interference fringes was visually observed and evaluated on the mirror surface decorative sheet under the condition of a three-wavelength region emission type (light source color: neutral white, symbol: EX-N) light source.

(Scratch resistance 1 Pencil hardness test)
A pencil hardness test was performed on the decorative plate.
The standard conformed to JIS5400, and was carried out at two levels, a load of 500 g and a load of 750 g.
The evaluation was made by observing scratches and dents on the surface.

(Scratch resistance 2 steel wool rubbing)
Steel wool rubbing was performed on the veneer.
Using steel wool (manufactured by Bonstar Sales Co., Ltd.), 5 levels of load were applied and 5 reciprocating rubbing was performed.
The load levels were 5 levels of 10 g / cm ² , 50 g / cm ² , 100 g / cm ² , 200 g / cm ² , and 500 g / cm ² .
The evaluation was made by observing scratches on the surface.

(Weatherability)
The decorative board was evaluated using a metal weather (manufactured by Daipla Wintes Co., Ltd.). Light energy: 65mW / m ²
Cycle: L (irradiation) + D (condensation) + R (darkness) = 20h + 4h + 0.01h
The evaluation method was evaluated by observing, after the test for 192 hours, coating film abnormalities such as color change or whitening of the hard coat layer, and the presence or absence of peeling of the hard coat layer.

<Evaluation result>
The evaluation results are shown in Table 1.

(Regarding interference fringes)
No difference was observed between Example 1 and Comparative Example 1, and interference fringes were only slightly generated in both cases. It is considered that this is because the thickness of the hard coat layer is 6 μm, which is within the thickness range of 4 μm to 8 μm according to the present invention.

(Scratch resistance 1 Regarding pencil hardness test)
No difference was found between Example 1 and Comparative Example 1.
That is, at a load of 500 g, the scratch-free pencil hardness is 3H, and a slight dent is observed by observation, but it is considered to be acceptable in practical use.

Further, at 750 g, the hardness of the pencil without scratches is 2H, and dents are observed by observation, but it is considered to be acceptable in practical use.

(Scratch resistance 2 Regarding steel wool rubbing)
No noticeable scratches were observed under any of the load conditions (10 g, 50 g, 100 g, 200 g, 500 g), and no difference was observed between the two. Practically, it is considered to be a pass.

(Regarding weather resistance)
A large difference was found between Example 1 and Comparative Example 1.
In Example 1, a slight yellowing was observed in the observation after the weather resistance test.
This is considered to be within the acceptable range in practice. That is, it is considered that this is due to the effect of the hard coat layer to which the ultraviolet absorber is added according to the present invention.

On the other hand, in Comparative Example 1, remarkable discoloration was observed, and in addition, peeling of the hard coat was observed. This is considered to be a practical problem. It is considered that this is due to the fact that no ultraviolet absorber is added to the hard coat layer.

As described above, according to the present invention, it is possible to verify that it is possible to provide a mirror surface decorative sheet having excellent mirror surface properties, excellent weather resistance, and excellent design properties, and a decorative board using the same surface decorative sheet. did it.

1 ... Thermoplastic resin base material Plastic film layer 2 ... Pattern layer 3 ... Dry laminate layer 4 ... Biaxially stretched polyethylene terephthalate film layer 5 ... Anchor layer 6 ... Hard coat layer 7 ... Primer layer 8 ... Adhesive layer 9 ... Base material layer 10 ... Mirror surface decorative sheet 20 ... Decorative board

Claims (3)

A decorative sheet composed of a thermoplastic base material plastic film layer, a pattern layer, and a biaxially stretched polyethylene terephthalate film layer.
A hard coat layer is provided on the outside of the biaxially stretched polyethylene terephthalate film layer by adding 0.2 to 0.6 parts by weight of a benzotriazole-based ultraviolet absorber to urethane acrylate to which a photoinitiator has been added. Mirror surface decorative sheet. The mirror-finished decorative sheet according to claim 1, wherein the hard coat layer has a thickness of 4 to 8 μm. A decorative board using the mirror-finished decorative sheet according to claim 1 or 2.

Images